Forging new generations of engineers Fluid Power Principles of EngineeringTM Unit 4 - Lesson 4.3 – Fluid Systems Forging new generations of engineers Project Lead The Way, Inc. Copyright 2007

Fluid Power

What is Fluid Power ? A system that transmits and controls energy through the use of pressurized liquid or gas Pneumatics - the media used is air Hydraulics - the media used is oil or water

What can Fluid Power Do ? Operation of system valves for air, water or chemicals Operation of heavy or hot doors Unloading of hoppers in building, steel making, mining and chemical industries Ramming and tamping in concrete and asphalt laying

What can Fluid Power Do ? Lifting and moving in slab molding machines Crop spraying Paint Spraying Holding and moving parts or assemblies in manufacturing

What can Fluid Power Do ? Jig (guides cutting tool) and Fixture (stationary work holding) clamping Forming operations of bending, drawing and flattening Bottling and filling machines Machine tool changing

What can Fluid Power Do ? Component and material conveyor transfer Robots Dentist drills vacuum lifting for thin sheet materials and much..much..more

Properties of Compressed Air Components have long working life resulting in longer system reliability Environmentally friendly Safety issues are minimized e.g.. Fire hazards; unaffected by overloads (actuators stall or slip) pneumatic actuators in a system do not produce heat (except for friction)

Properties of Gases Three important variables 1. Temperature, T 2. Pressure, P 3. Volume, V Gas laws describe relationships between these variables

Properties of Gases - Bernoulli’s Law When there is fluid flow through a tube of varying diameters the total energy in the system is constant the velocity is inversely proportional to the pressure V1 is less than V2 P1 is higher than P2

Properties of Gases (Boyle’s Law) The pressure of a given mass of gas is inversely proportional to its volume (providing the gas remains at constant temperature) Isothermic (equal temperature)

Properties of Gases (Boyle’s Law)

Properties of Gases (Charles’s Law) When the pressure of a confined gas remains constant, the volume of the gas is directly proportional to the absolute temperature. A given mass of gas increases in volume by 1/273 of its volume for every degree Celsius rise in temperature or 1/459.7 for every degree Fahrenheit rise in temperature. e.g. Hot air balloon

Properties of Gases (Charles’s Law continued) Isobaric - equal pressure V1 = T1 V2 T2 Where: V1 = initial volume V2 = resulting volume T1 = initial absolute temperature T2 = resulting absolute temperature A volume of air in an accumulator is submerged in a bucket of ice water (32 degrees F). If you remove the accumulator from the ice water and place it in a bucket of boiling water what would the resulting volume be. Fahrenheit Absolute is 460 + V2 = V1 x 672 492 V2 = V1 x T2 T1 = 1.36 V1

Properties of Gases (Pascal’s Law) Pressure at any point in a closed body of fluid is the same in all directions, exerting equal force on equal areas. Where: F = force P = pressure A = area F = P x A F P A Cover the letter you are trying to solve for e.g. P=F/A